The present invention concerns display products and pertains particularly to adjustments made to a liquid crystal display in order to improve display clarity when viewed at different viewing angles.
LCD video display panels require viewing angles close to perpendicular for optimum image accuracy and definition. Specifically, as the vertical angle changes in one direction, the image becomes brighter and has reduced contrast. In the other direction, the image darkens and has increased contrast.
Prior attempts to improve the image at non-perpendicular viewing angles have focused on changing the intensity of the backlight. This results in less overall brightness of the image, and in many cases increased electro-magnetic interference from the backlight.
In accordance with the preferred embodiment of the present invention, adjustments are made to a displayed image in order to take into account user viewing angle. Brightness values for colors are stored within palette registers. The palette registers, for example, are within a video controller. In response to a user indicating a view angle change, brightness values stored in at least some of the palette registers are changed. In the preferred embodiment, as brightness values are increased, contrast between color shades is decreased.
For example, the display is a liquid crystal display. Each palette register stores a red brightness value, a green brightness value and a blue brightness value. The user indicates a view angle change by either pressing a view angle index increment button, pressing a view angle index decrement button or via a viewing angle command.
In the preferred embodiment, backlight is left at full intensity, and viewing angle is compensated for only by adjusting the color palette to change the brightness and contrast range of the image. This results in improvement of overall image brightness and overall useful viewing angles.